Phase shifter film and process for the same

ABSTRACT

In the formation of a halftone type phase shift mask, a reactive gas introduction inlet and an inert gas introduction inlet are provided so as to introduce the respective gases separately and by using a reactive low throw sputtering method a molybdenum silicide based phase shifter film is formed. Thereby, it becomes possible to provide a halftone type phase shift mask, which is applicable to an ArF laser or to a KrF laser, by using molybdenum silicide based materials.

RELATED APPLICATION

This application is a divisional application of Ser. No. 09/804,158,filed Mar. 13, 2001 now U.S. Pat. No. 7,090,947, which is a continuationor continuation-in-part filed under 35 USC 111(a) of InternationalApplication No. PCT/JP00/04709, filed Jul. 13, 2000, which claimspriority of Japanese Patent application No. 11-199941 (P), filed Jul.14, 1999, and the contents of which are herewith incorporated byreference.

This application is a continuation of International Application No.PCT/JP00/04709, whose international filing date is Jul. 13, 2000, whichin turn claims the benefit of Japanese Patent Application No. 11-199941,filed Jul. 14, 1999, the disclosure of which Application is incorporatedby reference herein. The benefit of the filing and priority dates of theInternational and Japanese Applications is respectfully requested.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a phase shift mask, in particular to astructure of an attenuation type phase shift mask which attenuates lightof exposure wavelength and a process for the same.

2. Description of the Background Art

The making of semiconductor integrated circuits of large scale and theminiaturization thereof has been remarkable. Together with that theminiaturization of circuit patterns formed on semiconductor substrates(hereinafter referred to simply as wafers) has been progressing rapidly.

Particularly, photolithographic technology is widely recognized as abasic technology in pattern formation. Accordingly, a variety ofdevelopments and improvements have been carried out up to the presenttime. The miniaturization of patterns has been an unending process andthe requirements for the improved resolution of patterns have becomemore demanding.

Accordingly, in recent years, a phase shift exposure method using aphase shift mask has been proposed as a technology to satisfy theserequirements and “Phase Shift Mask and Process for the Same as well asExposure Method Using That Phase Shift Mask” (hereinafter referred to asbackground technology 1), disclosed in the Japanese Patent Laying-OpenNo. 5-285327(1993), “Process for Phase Shift Photo Mask Blanks, PhaseShift Photo Mask Blanks and Phase Shift Photo Mask” (hereinafterreferred to as background technology 2), disclosed in the JapanesePatent Laying-Open No. 8-74031(1996), and “Titanium Nitride Thin FilmFormation Method” (hereinafter referred to as background technology 3),disclosed in the Japanese Patent Laying-Open No. 8-127870(1996), aresited as a technology related to the above phase shift mask.

Background technologies 1 and 2 concretely disclose a molybdenumsilicide type halftone phase shift mask and a process for the same,wherein a reactive sputtering using a direct current magnetron dischargeis adopted in a film formation style of phase shifter film.

In addition, in background technology 1, as for supplied gases, Ar isused for an inert gas, 02 or (02+N2) is used for a reactive gas while amixture gas system is adopted as a gas supply system.

In addition, in background technology 2, as for supplied gases, Ar isused for an inert gas, NO is used for a reactive gas while a mixture gassystem is adopted as a gas supply system in the same way as inbackground technology 1.

In addition, in background technology 3, a reactive low pressuresputtering method through a direct current magnetron discharge and aunit therefore are concretely disclosed and the purpose of thisbackground technology 3 is to provide a titanium nitride thin filmformation method of which the filling in characteristics inside ofmicroscopic holes is maintained at an excellent level and of which thefilm thickness distribution of the thin film on the substrate surface isuniform.

In order to achieve this purpose, in background technology 3, aso-called long throw sputtering method (hereinafter referred to as LTSmethod) is adopted where the pressure is maintained at 1×10⁻¹ Pa(7.5×10⁻⁴ Torr) or less under an Ar+N2 gas atmosphere and the mixturegas composition is set at ⅛≦Ar/N2≦⅓ as a flow amount ratio in order togain a uniform titanium nitride thin film distribution. Here, as for thedistance (T/S) between the target and the substrate, 140 mm, 170 mm and200 mm are selected.

Based on the technologies shown in the above described backgroundtechnologies 1 to 3, however, in the case that a thin film which is usedas a phase shift mask, particularly a phase shifter film, is formed athin film which has sufficient optical characteristics (particularlytransmittance) cannot be formed.

In particular, a molybdenum silicide type phase shifter film which isformed based on background technologies 1 and 2 cannot be provided forpractical use because the transmittance of the halftone phase shift maskin the ArF laser exposure wavelength (193 nm) is very small.

In addition, film formation is possible only when the transmittance of ahalftone phase shift mask in the KrF laser exposure wavelength (248 nm)is less than 8% which becomes a problem in practical use.

Accordingly, this invention is provided to solve the above describedproblems and provides a halftone type phase shift mask which can beapplied in an ArF laser or a KrF laser by using a molybdenum silicidetype material. In addition, relating to this phase shift mask, theprovision of a process for the gaining of that phase shift mask inaddition to the provision of: a phase shifter film and a process for thesame, blanks for a phase shift mask and a process for the same, anexposure method by using that phase shift mask, a semiconductor devicemanufactured by using that phase shift mask, a defect inspection methodof that phase shift mask and a defect correction method of that phaseshift mask are additional purposes.

Based on this invention, as shown in the above described purposes, ahalftone phase shift mask which can be applied in an ArF laser or in aKrF laser can be formed of a molybdenum silicide type material. Sincethe same production process and production units as are used inbackground technologies 1 or 2 can be applied as they are for themolybdenum silicide type material a new large scale investment forfacilities can be avoided. It also becomes possible to save the labor,time and development costs which would be needed for developing a newproduction process.

More concretely, it becomes possible to form a molybdenum silicide typethin film through an LTS method, that is to say, a reactive sputteringmethod by means of direct current magnetron discharge so as to form athin film which has an excellent transmittance by applying the abovefilm to a phase shifter film and, thereby, it becomes possible tomanufacture a halftone type phase shift mask for ArF laser exposurewhich used to be impossible through a sputtering system as shown in thebackground technology.

SUMMARY OF THE INVENTION

The main structure of this invention is described in detail as follows.

In a sputtering system using an LTS method,

(i) the pressure is 7.5×10⁻⁴ Torr or less,

(ii) the distance (hereinafter referred to as the distance between T/S)between the target and the substrate is 100 mm or more, preferably, 400mm or more,

(iii) the flow amount ratio of the reactive gas to the inert gas is50%≦reactive gas/(reactive gas+inert gas)≦80% and, preferably, N₂O isused as the reactive gas and Ar is used as the inert gas.

(iv) As for a gas supply system, though either a mixture gas supplysystem wherein reactive gas and inert gas are mixed to be supplied intoa vacuum tank or a gas separation system wherein reactive gas is blownto the substrate while inert gas is supplied in the vicinity of thesputtering target is adoptable, the gas separation system is preferablebecause a better result can be gained.

Here, the reasons why the gas separation system is used and the distancebetween T/S is made to be 400 mm or more are shown as follows.

First, the reason why the gas separation system is preferable isdescribed as follows. In the mixture gas supply system, it cannot beavoided that the reactive gas reach the sputtering target surface withthe effect of oxidizing the surface of the target. A molybdenum silicideoxide film or a molybdenum silicide oxide nitride film which are formedon the surface of the molybdenum silicide target have the property ofelectrical insulation and, therefore, the deposition rate of the filmonto the substrate is rapidly lowered so as to result in the failure offilm formation when the reactive gas is supplied in the amount of apredetermined value or more.

Since the halftone type phase shifter film requires a hightransmittance, the restriction of the supply amount of this reactive gasis a very disadvantageous phenomenon and, therefore, this mixture gassupply system cannot fully take advantage of the LTS system. Incomparison with the background technology though a considerably improvedresult can, of course, be gained further improvement is desired.

Next, the reason why the distance between T/S is made to be 400 mm ormore is shown as follows. By making the distance between T/S be 400 mmor more and by adopting the gas separation system, the amount ofreactive gas, which has been supplied toward the substrate and whichreaches the sputtering target, becomes less so that the above describedproblems as shown in the mixture gas supply system can be avoided sincethe substrate and the sputtering target are fully separated.

Accordingly, it becomes possible to enhance the reactive gas ratio sothat a phase shifter film, of which the degree of oxidation andnitriding of molybdenum silicide is high, can be formed on the substrateand, therefore, it becomes possible to gain a phase shifter film whichhas a high transmittance in the exposure wavelength using an ArF laseror a KrF laser.

In the case that the distance between T/S is made to be less than 400mm, the effect of gas separation becomes insufficient so that themajority part of the reactive gas which has been supplied to thesubstrate reaches the sputtering target so as to exhibit unfavorableeffects.

Although, the molybdenum silicide oxide nitride film on the sputteringtarget surface causes an abnormal discharge and becomes the cause ofthin film defect generation, this is avoided in order to gain a phaseshift mask with a low defect level.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a configuration of a sputteringunit in which an LTS method is adopted;

FIG. 2 is a diagram showing a phase shifter film of each sample in anArF laser plotted based on its optical characteristics;

FIG. 3 is a diagram showing a phase shifter film of each sample in anKrF laser plotted based on its optical characteristics;

FIG. 4 is a cross section view of the structure of a phase shift maskaccording to a second embodiment based on this invention;

FIGS. 5A, 5B and 5C are schematic diagrams showing an electric field onthe mask and an electric field on the wafer in the case where a phaseshift mask is used based on this invention;

FIG. 6 is a cross section view showing the first step of a process for aphase shift mask according to the second embodiment based on thisinvention;

FIG. 7 is a cross section view showing the second step of a process fora phase shift mask according to the second and third embodiments basedon this invention;

FIG. 8 is a cross section view showing the third step of a process for aphase shift mask according to the second and third embodiments based onthis invention;

FIG. 9 is a cross section view showing the fourth step of a process fora phase shift mask according to the second and third embodiments basedon this invention;

FIG. 10 is a cross section view showing the first step of a process fora phase shift mask according to the third embodiment based on thisinvention;

FIG. 11 is a cross section view showing the first step of a process fora phase shift mask according to a fourth embodiment based on thisinvention;

FIG. 12 is a cross section view showing the second step of a process fora phase shift mask according to the fourth embodiment based on thisinvention;

FIG. 13 is a cross section view showing the third step of a process fora phase shift mask according to the fourth embodiment based on thisinvention;

FIG. 14 is a cross section view showing the fourth step of a process fora phase shift mask according to the fourth embodiment based on thisinvention;

FIG. 15 is a cross section view showing the fifth step of a process fora phase shift mask according to the fourth embodiment based on thisinvention;

FIGS. 16A and 16B are cross section views of blanks for a phase shiftmask according to a fifth embodiment based on this invention;

FIGS. 17A and 17B are cross section views showing a process for blanksfor a phase shift mask according to the fifth embodiment based on thisinvention;

FIG. 18 is a cross section view showing a defect correction method of aphase shift mask based on this invention;

FIG. 19 is a schematic diagram showing a condition of an exposure methodusing a phase shift mask based on this invention;

FIG. 20 is a diagram showing the relationship between the focus shiftand the contact hole size in an exposure method using a phase shift maskbased on this invention;

FIG. 21 is a diagram showing the relationship between the focus shiftand the contact hole size in an exposure method using a photo maskaccording to a prior art; and

FIG. 22 is a diagram comparing the relationship between the coherencyand the focal depth in an exposure method using a phase shift mask basedon this invention versus that in an exposure method using a phase shiftmask according to the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, each embodiment based on this invention is described.

First Embodiment

First, referring to FIG. 1 a sputtering unit for forming a phase shiftfilm based on this invention by using an LTS method is described.

The sputtering unit as shown in FIG. 1 is a schematic diagram showingthe configuration of a sputtering unit 1000 which can implement an LTSmethod.

This sputtering unit 1000 includes a low pressure vacuum tank 3. Thevacuum tank 3 has a reactive gas inlet 14 a, an inert gas inlet 14 b anda mixture gas inlet 14 c. In addition, it has two vacuum exhaust outlets14 d and a vacuum exhaust outlet 14 e. It also has a target electrode 5and a substrate holder 7.

A vacuum pump, which is not shown, is connected to the vacuum exhaustoutlets 14 d and the vacuum exhaust outlet 14 e while a magnet plate 9,which has magnets 10 arranged in double concentric circles, is providedon the back side of the target electrode 5 and a heater 11 is providedon the backside of the substrate holder 7. At the time of film formationmolybdenum silicide is used as a target.

EXAMPLE 1

Next, concrete film formation conditions in Example 1 of film formationof molybdenum silicide oxide nitride film are described as follows.

T/S distance: 400 mm

sputtering current: 1.7 A to 3.2 A

sputtering voltage: 530V to 570V

sputtering power: 1 kW

substrate temperature: 50 degrees (° C.) to 120 degrees (° C.)

film thickness: 740 A to 3300 A

sputtering time: 7 min to 12 min (stationary film formation)

28 min to 56 min (rotational film formation)

gas separation system: blowing of reactive gas to substrate supply ofinert gas to target

Under the above described conditions the gas flow amount rate (%:Ar/N₂O), the gas flow amount (sccm), the pressure (×10⁻⁴ Torr), thedeposition rate (Å/min), the film formation system and the gas supplysystem are appropriately selected so that the samples TO1 to TO9, TR3,4, 6, TA1 to TA4, which have been formed in films, are shown in Table 1below.

TABLE 1 Film Formation Conditions TO1 ~ (Embodiment) Example 1 Gas flowGas flow Film Reactive amount ratio % amount SCCM Pressure Depositionformation gas supply Sample Ar N₂O Ar N₂O (×10⁻⁴ Torr) rate Å/min systemsystem Note TO1 44.44 55.56 12 15 4.6 205 Stationary Gas T/S400 mm TO237.5 62.5 12 20 4.9 207 film separation TO3 32.43 67.57 12 25 5.6 206.2formation TO4 28.57 71.43 12 30 5.9 193.8 TO5 28.57 71.43 12 30 6.0190.4 TO6 25.33 74.47 12 35 6.9 181.2 TO7 23.08 76.92 12 40 8.0 120 TO821.05 78.95 12 45 8.8 110.4 TO9 18.03 81.97 11 50 9.6  88.75 TR3 32.4367.57 12 25 5.3 439.8*¹ Rotational Gas TR4 28.57 71.43 12 30 6.2 416.5*¹film separation TR6 25.53 74.47 12 35 6.8 380.2*¹ formation TA1 0 100 030 4/2  90.62 Stationary Gas TA2 9.09 90.91 3 30 4.6 105.7 filmseparation TA3 50.82 49.18 31 30 10 210.8 formation TA4 76.56 23.44 9830 30 200 *¹value converted to stationary formed film (=7.243 × filmthickness of rotationally formed film)

EXAMPLE 2

Next, concrete film formation conditions in Example 2 of film formationof molybdenum silicide oxide nitride film are described as follows.

T/S distance: 400 mm

sputtering current: 1.7 A to 3.2 A

sputtering voltage: 530V to 570V

sputtering power: 1 kW

substrate temperature: 50 degrees (° C.) to 120 degrees (° C.)

film thickness: 740 Å to 3300 Å

sputtering time: 7 min to 12 min (stationary film formation)

mixture gas system: mixing of reactive gas and inert gas so as to besupplied into vacuum tank

Under the above described conditions the gas flow amount rate (%:Ar/N₂0), the gas flow amount (sccm), the pressure (×10⁻⁴ Torr), thedeposition rate (Å/min), the film formation system and the gas supplysystem are appropriately selected so that the resultant samples TMX1 toTMX3, which have been formed in films, are shown in Table 2 below.

TABLE 2 Film Formation Conditions TMX1 ~ (Embodiment) Example 2 TMX1 8020 24 6 4.6 210 Rotational Mixture TMX2 70 30 21 9 4.6 215 film Gas TMX365 35 19.5 10.5 4.6 220 formation system

EXAMPLE 3

Next, concrete film formation conditions in Example 3 of film formationof molybdenum silicide oxide nitride film are shown as follows.

T/S distance: 400 mm

sputtering current: 1.92 A to 2.13 A

sputtering voltage: 465V to 524V

sputtering power: 1 kW

substrate temperature: 30 degrees (° C.) to 130 degrees (° C.)

film thickness: 830 A to 1300 A

sputtering time: 4 min to 10 min (stationary film formation) gasseparation system: blowing of reactive gas to substrate

supply of inert gas to target

Under the above described conditions the gas flow amount rate (%:Ar/N₂0), the gas flow amount (sccm), the pressure (×10⁻⁴ Torr), thedeposition rate (Å/min), the film formation system and the gas supplysystem are appropriately selected so that the samples TS 1 to TS4, TS6,TS7, which have been formed in films, are shown in Table 3 below.

TABLE 3 Film Formation Conditions TS 1 ~ (Embodiment) Example 3 Gas flowGas flow Film Reactive amount ratio % amount SCCM Pressure Depositionformation gas supply Sample Ar N₂O Ar N₂O (×10⁻⁴ Torr) rate Å/min systemsystem Note TS1 44.44 55.56 12 15 4.5 207.5 Stationary Gas T/S400 mm TS237.5 62.5 12 20 4.8 222.6 film separation TS3 32.43 67.57 12 25 5.3206.2 formation TS4 28.57 71.43 12 30 6.0 200 — — — — — — TS6 25.3374.47 12 35 6.8 208.3 TS7 23.08 76.92 12 40 8.0 135.1

EXAMPLE 4

Next, concrete film formation conditions in Example 4 of film formationof molybdenum silicide oxide nitride film are described as follows. Herein the present example, the molybdenum silicide oxide nitride film has atwo layer structure as described in FIG. 7.

T/S distance: 400 mm

sputtering current: (upper layer) 1.91 A to 1.95 A

-   -   (lower layer) 2.05 A to 2.19 A

sputtering voltage: (upper layer) 515V to 526V

-   -   (lower layer) 454V to 495V

sputtering power: (upper layer: lower layer) 1 kW

Substrate temperature: (upper layer: lower layer) 79 degrees (° C.) to139 degrees (° C.)

entire film thickness: 900 A to 1100 A

sputtering time: (upper layer) 1.5 min (stationary film formation)

-   -   (lower layer) 3 min to 7 min (rotational film formation)

gas separation system: blowing of reactive gas to substrate

-   -   supply of inert gas to target

Under the above described conditions the gas flow amount rate (%:Ar/N₂0), the gas flow amount (sccm), the pressure (×10⁻⁴ Torr), thedeposition rate (A/min), the film formation system and the gas supplysystem are appropriately selected so that the resultant samples TM1 toTM4, which have been formed in films, are shown in Table 4 below.

TABLE 4 Film Formation Conditions TM1 ~ (Embodiment) Example 4 Filmthickness Sampl Å Entire layer dTOT Gas flow Gas flow Film ReactiveUpper layer dU amount ratio % amount SCCM Pressure Deposition formationgas supply Lower layer dL Ar N₂O Ar N₂O (×10⁻⁴ Torr) rate Å/min systemsystem Note TM1 971 — — — — — — Stationary Gas T/S400 mm TU1 300 44.4455.56 12 15 4.6 200 film separation T/S: TL4 671 28.57 71.43 12 30 7.5236.8 formation distance TM2 1117.8 — — — — — — between TU2 300 37.506.250 12 20 4.9 200 target and TL7 817.8 23.08 76.92 12 40 7.9 169.2substrate TM3 1117.8 — — — — — — TU3 300 32.43 67.57 12 25 5.6 200 TL7a817.8 23.08 76.92 12 40 8.0 163.6 TM4 1166.8 — — — — — — TU3a 300 32.4367.57 12 25 5.3 200 TL8 866.8 21.05 78.95 12 45 8.8 123.8

EXAMPLE 5

Here, for reference, film formation conditions of molybdenum silicideoxide nitride film according to the background technology as Example 5are described as follows.

T/S distance: 80 mm

gas separation system: blowing of reactive gas to substrate

-   -   supply of inert gas to target

Under the above described conditions the gas flow amount rate (%:Ar/N₂0), the gas flow amount (sccm), the pressure (×10⁻⁴ Torr), thedeposition rate (Å/min), the film formation system and the gas supplysystem are appropriately selected so that the resultant samples Q1-1 toQ1-4 and Q3-1 to Q3-3, which have been formed in films, are shown inTable 5 below.

TABLE 5 Film Formation Conditions Q1-1 ~ (Background Technology) Gasflow Gas flow Film Reactive amount ratio % amount SCCM PressureDeposition formation gas supply Sample Ar N₂O Ar N₂O (×10⁻⁴ Torr) rateÅ/min system system Note Q1-1 92.00 8.00 230 20 60 683.4*¹ RotationalSeparation T/S80 mm Q1-2 88.46 11.54 230 30 60 735.2 film Q1-3 86.7913.21 230 35 62 704.2 formation Q1-4 85.18 14.81 230 40*² 62 683 Q3-191.95 8.05 120 10.5 70 40216 In-line Separation T/S103 mm Q3-2 91.958.05 120 10.5 70 416.8 film Q3-3 89.55 10.45 120 40*³ 76 445.1 formation*¹value converted to stationary formed film (=17 × film thickness ofrotationally formed film) *²when N₂O is supplied of 45 SCCM or more thedeposition rate is dramatically reduced since the sputtering target isoxidized *³when N₂O is supplied of 80 SCCM or more the deposition rateis dramatically reduced since the sputtering target is oxidized

Next, optical characteristics of each sample as shown in the aboveExamples 1 to 4 (Tables 1 to 4) with respect to an ArF laser (193 nm), aKrF laser (248 nm) and an i-line (365 nm) are shown in the followingTable 6 “ArF laser (193 nm),” the following Table 7 “KrF laser (248 nm)”and the following Table 8 “i-line (365 nm).” Here, all of theserespective samples are in the condition of “as deposited.”

TABLE 6 Optical Characteristics T01 ~ (Embodiment), Condition asDeposited Inspection ArF laser (193 nm) wavelength Optical Film Phase(365 nm) constant thickness ds Transmittance difference TransmittanceSample n k Å % ° % Note TO1 2.450 0.8440 687.1 1.743 179.1 15.75 TO22.222 0.6180 807.8 3.310 179.6 25.72 TO3 2.226 0.5560 802.7 4.413 179.533.74 TO4 2.228 0.5328 800.4 5.02 179.4 26.08 TO5 2.278 0.5386 769.35.366 179.3 36.90 TO6 2.110 0.4727 882 5.476 179.5 37.47 TO7 1.9330.3730 1045 6.744 179.7 43.42 TO8 1.815 0.3014 1194 8.34 179.8 60.82 TO91.759 0.2902 1282 7.795 179.8 65.89 TR3 2.337 0.5955 737.6 4.491 179.335.58 TR4 2.245 0.3612 782.9 12.80 178.8 36.15 TR6 2.049 0.4559 922.05.252 179.6 36.10 TA1 1.810 0.2657 1200 10.87 179.9 70.45 TA2 1.8270.2720 1176 10.77 179.9 63.7 TA3 — — — — — — TA4 1.985 0.6076 1002 1.623180.0 23.67 TMX1 2.194 6201 826.8 2.887 179.6 23.08 TMX2 2.131 0.5641970.5 3.370 179.7 25.7 TMX3 2.00 0.4522 978.5 4.471 179.7 33.2

TABLE 7 Optical Characteristics TO1 ~, KrF exposure light wavelength,Condition as Deposited Inspection ArF laser (193 nm) wavelength OpticalFilm Phase (365 nm) constant thickness ds Transmittance differenceTransmittance Sample n k Å % ° % Note TO1 2.262 0.8736 1016 0.895 179.16.74 TO2 2.171 0.5881 1082 3.259 179.5 15.91 TO3 2.110 0.4762 1134 5.380179.4 20.79 TO4 2.030 0.4334 1220 5.798 179.5 20.68 TO5 2.046 0.43701201 5.889 179.4 20.66 TO6 1.934 0.3853 1342 9.248 1796 22.30 TO7 1.8240.3007 1517 8.632 179.8 30.44 TO8 1.754 0.2380 1655 11.96 179.8 51.62TO9 1.812 0.2208 1536 15.57 180.0 60.50 TR3 2.111 0.4841 1134 5.147179.4 19.98 TR4 1.990 0.4423 1269 4.944 179.5 19.10 TR6 1.912 0.37801374 6.197 179.6 22.34 TA1 1.800 0.1975 1558 18.27 180.1 62.70 TA2 1.7640.2141 1633 14.91 179.9 53.70 TA3 2.213 0.5139 1123 4.442 179.4 19.90TA4 1.939 0.5181 1344 2.531 179.7 15.13 TMX1 2.054 0.5997 1202.6 2.17317.02 11.97 TMX2 2.003 0.5312 1259 2.869 179.7 14.26 TMX3 1.899 0.39431394.4 5.327 179.5 21.21

TABLE 8 Optical Characteristics T01 ~, i · line exposure lightwavelength, Condition as Deposited Inspection ArF laser (193 nm)wavelength Optical Film Phase (365 nm) constant thickness dsTransmittance difference Transmittance Sample n k Å % ° % Note TO1 2.4520.6827 1289 3.654 178.8 3.65 TO2 2.261 0.4202 1465 9.652 178.6 9.65 TO32.167 0.3376 1578 13.20 179.0 13.20 TO4 2.098 0.3200 1677 13.24 179.313.24 TO5 2.104 0.3247 1668 12.99 179.3 12.99 TO6 2.000 0.2813 183914.38 179.8 14.38 TO7 1.854 0.1974 2149 20.10 180.2 20.10 TO8 1.7910.0910 2313 42.06 180.6 10.57 TO9 1.733 0.0673 2494 48.87 180.3 48.87TR3 2.162 0.3488 1586 12.32 179.0 12.32 TR4 2.063 0.3289 173 11.86 179.411.86 TR6 1.970 0.2766 1896 14.08 179.9 14.08 TA1 1.706 0.0612 258950.73 180.1 50.73 TA2 1.701 0.0875 2610 40.07 180.0 40.07 TA3 2.1820.3514 1559 12.49 178.9 12.45 TA4 2.068 0.3638 1726 9.683 179.4 9.683TMX1 2.178 0.4549 1571.2 6.996 179.0 6.996 TMX2 2.110 0.3980 1662.38.544 179.1 8.54 TMX3 1.973 0.2840 189.04 13.48 179.8 13.48

Next, the optical constants of the samples TS1 to TS4, TS6 and TS7 whichhave been formed to a film in the above described Example 2 with respectto an ArF laser (193 nm), a KrF laser (248 nm) and an i-line (365 nm)are shown in Table 9 below. Here, these samples are sintered products towhich a heat treatment of 350 degrees (° C.) and 3 hr is applied.

TABLE 9 Optical Characteristics TS1 ~, respective wavelengths, 350degrees(° C.), 3 hr, sintered product ArF laser KrF laser i · line 193nm 248 nm 365 nm Sample n k n k N k Note TS1 2.429 0.9140 2.268 0.78352.362 0.6174 TS2 2.260 0.5895 2.124 0.4703 2.153 0.3127 TS3 2.300 0.56682.120 0.4461 2.141 0.3122 TS4 1.909 0.4564 1.969 0.3643 2.001 0.2636 TS61.892 0.3963 1.913 0.3120 1.852 0.2216 TS7 1.722 0.2678 1.781 0.19761.714 0.0445

Next, the optical constants of the samples TM1 to TM4, which have beenformed to a film in the above described Example 4 with respect to an ArFlaser (193 nm) and an inspection wavelength (248 nm, 365 nm) are shownin Table 10 below. Here, these samples are sintered products to which aheat treatment of 350 degrees (° C.) and 3 hr is applied.

TABLE 10 Optical Characteristics TM1 ~, ArF laser, 350 degrees(° C.), 3hr, sintered product ArF Laser Inspection wavelength (193 nm) 365 nmPhase 248 nm Phase Transmittance difference Transmittance differenceSample n % k deg. n % k deg. Note TM1 2.1 −175 4.48 22.68 TM2 4.88 −17613.81 33.44 TM3 5.87 −180 16.99 36.70 TM4 8.98 −177 18.36 42.44

Next, the optical characteristics of the samples Q1-1 to Q1-4 which havebeen formed to a film in the above described background technology withrespect to an ArF laser (193 nm) and an inspection wavelength (365 nm)are shown in the following Table 11. Here, these samples are in thecondition as deposited. And data of the samples Q3-1 to Q3-3 cannot begained.

TABLE 11 Optical Characteristics Q1-1 ~, ArF exposure light wavelength,Condition as Deposited Inspection ArF laser (193 nm) wavelength OpticalFilm Phase (365 nm) constant thickness ds Transmittance differenceTransmittance Sample n k Å % ° % Note Q1-1 2.278 0.6820 774.4 2.557179.5 21.94 Q1-2 2.018 0.5476 966.2 2.696 179.8 30.63 Q1-3 1.979 0.4587999.9 4.285 179.7 27.94 Q1-4 1.939 0.3962 1039 5.848 179.6 38.78 Q3-1 —— — — — — Q3-2 — — — — — — Q3-3 — — — — — —

Next, the optical characteristics of the samples Q1-1 to Q1-4 and Q3-1to Q3-3 which have been formed to a film in the above describedbackground technology with respect to a KrF laser (248 nm) and aninspection wavelength (365 nm) are shown in the following Table 12.Here, these samples are in the condition as deposited.

TABLE 12 Optical Characteristics Q1-1 ~, KrF exposure light wavelength,Condition as Deposited Inspection KrF laser (248 nm) wavelength OpticalFilm Phase (365 nm) constant thickness ds Transmittance differenceTransmittance Sample n k Å % ° % Note Q1-1 2.053 0.6701 1207.2 1.401179.6 9.682 Q1-2 1.960 0.4614 1310.4 3.998 179.6 20.30 Q1-3 1.906 0.36831382.7 6.526 179.6 27/30 Q1-4 1.847 0.3258 1477.2 7.584 179.7 26.60 Q3-12.040 0.9166 1234 0.2776 179.3 3.146 Q3-2 2.073 0.9062 1196 0.3496 179.33.421 Q3-3 2.017 0.7308 1253 0.826 179.6 6.79

Next, the optical characteristics of the samples Q1-1 to Q1-4 and Q3-1to Q3-3 which have been formed to a film in the above describedbackground technology with respect to an i-line (365 nm) and aninspection wavelength (365 nm) are shown in the following Table 13.Here, these samples are in the condition as deposited.

TABLE 13 Optical Characteristics Q1-1 ~, i · line exposure lightwavelength, Condition as Deposited Inspection i · line (365 nm)wavelength Optical Film Phase (365 nm) constant thickness dsTransmittance difference Transmittance Sample n k Å % ° % Note Q1-12.213 0.5034 1529.9 5.724 179.1 5.724 Q1-2 2.042 0.3066 1766.4 13.14179.6 13.14 Q1-3 1.971 0.2395 1892 18.04 180.0 18.04 Q1-4 1.905 0.22712029.3 17.65 180.1 17.65 Q3-1 2.321 0.7553 1421 1.953 179.1 1.953 Q3-22.333 0.7576 1408 1.989 179.0 1.989 Q3-3 2.209 0.5702 1541 3.941 179.33.941

Next, based on the contents of Tables 1 to 12 which show the abovedescribed film formation conditions, the evaluation of phase shift filmsincluding a molybdenum silicide oxide nitride film is shown as follows.

(Evaluation 1)

The evaluation of a phase shift film including a molybdenum silicideoxide nitride film in the case that the reactive gas is introduced inthe separation condition as shown in the above described Example 1 isdescribed.

First, FIGS. 2 and 3 show a diagram indicating n values of the opticalconstants (n−i×k: n; refractive index, k; extinction coefficient) alongthe horizontal axis and k values along the vertical axis wherein theoptical characteristics of the samples TO1 to TO9, TR3, 4, 6 and TA1 toTA4 as shown in Tables 1, 6 and 7 are plotted. Here, FIG. 2 concerns anArF laser (193 nm) and FIG. 3 concerns a KrF laser (248 nm).

As shown in Tables 6 and 7 as well as in FIGS. 2 and 3, a phase shiftfilm, which has a high quality of 8% or more of transmittance, can begained in the samples T08, TR4, TA1, TA2 and TA4 with respect to an ArFlaser (193 nm).

In addition, a phase shift film, which has a high quality of 8% or moreof transmittance, can be gained in the samples T06 to T09 and in TA1 andTA2 with respect to a KrF laser (248 nm).

(Evaluation 2)

The evaluation of a phase shift film including a molybdenum silicideoxide nitride film in the case that the reactive gas is introduced inthe mixed condition as shown in the above Example 2 is described.

In the same manner as in Evaluation 1, FIGS. 2 and 3 show a diagramindicating n values of the optical constants (n−i×k) along thehorizontal axis and k values along the vertical axis wherein the opticalcharacteristics of the samples TMX1 to TM3 as shown in Tables 2, 6 and 7are plotted. Here, FIG. 2 concerns an ArF laser (193 nm) and FIG. 3concerns a KrF laser (248 nm).

As shown in Tables 6 and 7 as well as in FIGS. 2 and 3, in the case thatthe reactive gas is introduced in the mixed condition, though a phaseshift film which has such a high quality as in Evaluation 1 cannot begained, it is possible to form a phase shift film of which thetransmittance is relatively high such that the transmittance of thesample TMX3 is 4.471% with respect to an ArF laser (193 nm) and thetransmittance of the sample TMX3 is 5.327% with respect to a KrF laser(248 nm).

(Evaluation 3)

The evaluation of a phase shift film including a molybdenum silicideoxide nitride film shown as the samples TS1 to TS4, TS6 and TS7 inTables 3 and 9 as shown in the above Example 3 is described.

A double layer structure is adopted in the samples TS 1 to TS4, TS6 andTS7 as shown in Table 9 where a film of which the absorption is high andof which the chemical resistance properties are excellent is formed asthe upper layer while a film of which the absorption is low and of whichthe chemical resistance properties are poor is formed as the lowerlayer. By using the double layer structure the transmittance for theinspection wavelength (365 nm) is designed to be less than approximately40%. This principle is the same as in background technology 2.

As for the film formation conditions for each layer of the double layerfilm as shown in Table 3, either of the set of film formation conditionsas shown in Table 3 is adopted. The corresponding relationship meansthat, in the case that the N2O gas flow amount as shown in Table 3 andthe N₂O gas flow amount in the upper layer or in the lower layer ofTable 4 are the same then other film formation conditions are also thesame.

(Evaluation 4)

The evaluation of a phase shift film including a molybdenum silicideoxide nitride film shown as the samples TM1 to TM4 in Tables 4 and 10and the samples TS1 to TS6 and TS7 in Table 9 as shown in the aboveExample 4 is described.

The n values and k values of the samples TS1 to TS6 and TS7 as shown inTable 9 have the optical characteristics which guarantee thecharacteristics of Table 10. Table 10 shows the evaluation of the twolayers which have the film structure and which are formed according tothe film formation conditions as in Table 4 which investigates whetheror not the optical characteristics of the samples TM1 to TM4, to whichsintering processing of 350 degrees (° C.) and 3 hr is applied, areapplicable as blanks for a halftone phase shift mask in a photo mask forArF laser exposure.

As is seen in Table 10, the phase difference of 175° to 180° in the ArFexposure wavelength and the transmittance of 2% to 9% are gained whilethe transmittance of less than 42.5% is gained for the defect inspectionwavelength of 365 nm, and, therefore, it is shown that the samples aresufficiently available for practical use.

Second Embodiment

Next, a phase shift mask, which has the above described phase shifterfilm and a method thereof, are described in the following. First,referring to FIG. 4, the structure of a halftone type phase shift maskin this second embodiment is described. This halftone type phase shiftmask includes a transparent substrate 1 made of crystal, which transmitsexposure light, and a phase shift pattern 30 formed on the main surfaceof this transparent substrate 1. This phase shift pattern 30 isconfigured of the first light transmission part 10, wherein thetransparent substrate 1 is exposed, and of the second light transmissionpart 4, wherein the phase and the transmittance of the transmittedexposure light is converted by approximately 180° with respect to thephase of exposure light, which transmits through the first lighttransmission part 10, and which has a necessary transmittance (forexample 1% to 40%) and is made of a single material.

Next, referring to FIGS. 5A, 5B, 5C the electric field on the mask ofexposure light, which transmits the phase shift mask 200 having theabove described structure, and light intensity on the wafer, aredescribed.

Referring to FIG. 5A, a cross section view of the above described phaseshift mask 200 is shown. Referring to FIG. 5B, since the electric fieldon the mask is inverted in the phase at the edge of the exposurepattern, the electric field always becomes 0 at the edge parts of theexposure pattern. Therefore, referring to FIG. 5C, the difference of theelectric field on the wafer between the light transmission part 10 andthe phase shift part 4 of the exposure pattern becomes sufficient sothat it becomes possible to gain a high resolution.

Next, with respect to a process for a phase shift mask 200, the casewhere a molybdenum silicide oxide nitride film is used as a phaseshifter film is described.

FIGS. 6 to 9 are cross section structural views showing the process inaccordance with the cross section of the phase shift mask 200 as shownin FIG. 3.

First, referring to FIG. 6, a phase shifter film 4 made of a molybdenumsilicide oxide nitride film is formed on the transparent substrate 1 byusing the LTS method. Here, under the same film formation conditions asin the above described sample T03 of Table 1, a phase shifter film 4made of a single layered molybdenum silicide oxide nitride film isformed to have the film thickness of approximately 1134 Å.

In this case, blanks for a phase shift mask of the wavelength of 248 nmand the phase shift amount of approximately 180 degrees can be gained.In this manner, the phase shifter film 4 formed on the transparentsubstrate 1 is referred to as blanks for a phase shift mask.

After that, a heat treatment of 200 degrees (° C.) or more is carriedout by using a clean oven, or the like, in order to stabilize thetransmittance of this phase shifter film 4.

Thereby, the fluctuation of the transmittance (0.5 to 1.0%) due to theheat treatment (approximately 180 degrees (° C.) such as in a resistapplication process for the film formation of a conventional phaseshifter film can be prevented.

Next, on this phase shifter film 4, a resist film 5 for an electron beam(Zeon Corporation: ZEP-810S (registered trademark)), or the like, isformed so as to have the film thickness of approximately 5000 Å. Afterthat, a static charge prevention film 6 (made by Showa Denko: Espacer100 (registered trademark)), or the like, is formed approximately 100 Åin order to prevent the static charge at the time of exposure of anelectron beam since the molybdenum silicide oxide nitride film is notconductive.

Next, referring to FIG. 7, the resist film 5 for an electron beam isexposed with an electron beam and the static charge prevention film 6 isremoved through cleaning with water. After that, by developing theresist film 5, the resist film 5 with a predetermined resist pattern isformed.

Next, referring to FIG. 8, the phase shifter film 4 is etched by usingthe above described resist film 5 as a mask. As for the etching deviceat this time, a parallel plate type RF ion etching device is used andthe etching is carried out for the etching time of approximately 11minutes with the distance between electrode substrates being 60 mm, theoperational pressure being 0.3 Torr and through the use of CF4+02reactive gases with respective flow amounts of approximately 95 sccm andapproximately 5 sccm.

Next, referring to FIG. 9, the resist film 5 is removed. As describedabove, a phase shift mask in this second embodiment is completed.

Third Embodiment

Next, the case where halftone phase shift mask blanks for ArF laserexposure are formed under the same film formation conditions as in theabove described sample TM3 in Table 4 is described. Referring to FIG.10, a lower layer phase shifter film 4L made of molybdenum silicideoxide nitride film with the film thickness of approximately 818 Å isformed on the number 6025 crystal substrate under the film formationconditions of TM3 in Table 4.

After that, an upper layer phase shifter film 4U made of a molybdenumsilicide oxide nitride film with the film thickness of approximately 300Å is formed on the above lower layer phase shifter film 4L. These lowerlayer phase shifter film 4L and upper layer phase shifter film 4U formthe phase shifter film 4.

Next, a sintering process is carried out on the phase shifter film 4formed of this two layer structure in the atmosphere of 350 degrees (°C.) for 3 hours so as to complete the phase shift mask blanks.

The optical characteristics of the phase shift mask blanks which havebeen gained in such a manner correspond to the sample TM3 of Table 10and exhibit the transmission of approximately 6%, the phase gap ofapproximately 180 degrees (° C.) with the wavelength of 193 nm.

The evaluation of the phase difference is carried out by a phasedifference gauge for the ArF wavelength made by Laser Tech Co. Ltd. andthrough calculation of the optical constant. The transmittance for thedefect detection wavelength of 365 nm is 36%.

A predetermined pattern is formed on the phase shifter film 4 throughthe same steps as in the above described first embodiment by using thegained halftone phase shift mask blanks for ArF laser exposure. Inaddition, as for the evaluation of the phase shift film the sameevaluation as in the above (Evaluation 3) is gained.

Here, though in the above described first to third embodiments the casewhere the distance between T/S is 400 mm is described, a range of 100 mmto 600 mm can be applied due to an application field.

In addition, though in the above first to third embodiments N₂0 isutilized as a reactive gas, it is possible to utilize NO, N2+O2 or amixture gas containing these. In addition, though Ar is utilized as aninert gas, it is possible to use other inert gases (gases which belongto group O of the periodic table) such as He, Ne, and Kr.

In addition, though in each of the above described embodiments, the LTSmethod is applied for a molybdenum silicide type halftone phase shifterfilm, metal fluoride such as CrFx, metal silicide oxide such as ZrSiOxor metal silicide oxide nitride such as ZrSiOxNy are cited as othermaterials for the halftone phase shifter film.

Fourth Embodiment

Next, the fourth embodiment based on this invention is described. Inthis third embodiment a metal film for static charge prevention at thetime of exposure by electron beam or a laser light is formed on thephase shifter film in a process for a phase shift mask.

In the following, referring to FIGS. 11 to 15, a process for a phaseshifter film is described. FIGS. 11 to 15 show a cross sectionstructural view corresponding to the cross section of the phase shiftmask as shown in FIG. 1.

First, referring to FIG. 11, a phase shifter film 4 made of a molybdenumsilicide oxide nitride film is formed on the transparent substrate 1 inthe same manner as in the first or second embodiment.

After that, a static charge prevention film 6 with the film thickness ofapproximately 100 to 500 Å is formed on this phase shifter film 4. Asfor the film quality of this static charge prevention film 6, amolybdenum film is formed since the film quality of the phase shifterfilm is Mo based. This is because the phase shifter film 4 made ofmolybdenum silicide oxide nitride which is formed through the abovedescribed method is not conductive. After that, a resist film 5 for anelectron beam with the film thickness of approximately 5000 Å is formedon the above static charge prevention film 6.

Next, referring to FIG. 12, a resist film 5 with a desired resistpattern is formed by exposing predetermined positions of the resist film5, for an electron beam, with an electron beam and by developing it.

Next, referring to FIG. 13, in the case that the static chargeprevention film 6 is Mo based, the static charge prevention film and thephase shifter film 4 are sequentially etched through dry etching byusing CF4+02 gas and by using the resist film 5 for an electron beam asa mask.

Next, referring to FIG. 14, the resist film 5 is removed by using O2plasma, or the like. After that, referring to FIG. 15, the static chargeprevention film 6 is etched and removed by using etching liquid (cericammonium nitrate/perchloric acid mixture solution), or the like.

Thereby, the phase shift mask is completed.

Here, though in the etching of the above described phase shift mask, inthe case that the phase shift mask is MoSi based, a static chargeprevention film made of a molybdenum film is formed, the invention isnot limited to this and in the case that the phase shift mask is Crbased, an MoSi film may be used as a static charge prevention film or inthe case of an Mo based phase shifter film a Cr based static chargeprevention film may be used so that the same working effects can begained.

As described above, by providing a molybdenum film at the time of themanufacturing steps for a phase shift mask, it becomes possible toprevent a static charge at the time of electron beam exposure and italso becomes possible to make the film serve as an optical reflectionfilm of the optical position detector.

Here, though in the present embodiment, a molybdenum film is used as astatic charge prevention film, metal films which can gain the sameeffects, for example, films of W, Ta, Ti, Si, Al or, alloys thereof, maybe used.

Fifth Embodiment

A structure of blanks for a phase shift mask used in the aboveembodiment is described as the fifth embodiment referring to thefollowing FIGS.

As for the structure of blanks for a phase shift mask used in the abovedescribed embodiment, two types of structures can be cited as shown inFIGS. 16A and 16B. In the structure as shown in FIG. 16A, the phaseshifter film 4 is formed on the transparent substrate 1 while in thestructure as shown in FIG. 16B, the phase shifter film 4 is formed onthe transparent substrate 1 and, in addition, the metal film 6 is formedon this phase shifter film 4.

In the case that a phase shift mask is formed by using these blanks fora phase shift mask, the formation procedure differs depending on thedrawing device for exposing the resist film 4. For example, (1) the casewhere the resist film is exposed by utilizing an electron beam and (2)the case where the resist film is exposed by utilizing a laser havedifferent formation procedures.

(1) The case where the resist film is exposed by utilizing an electronbeam

First, the case where the resist film is exposed by utilizing anelectron beam is described referring to FIGS. 17A and 17B.

In the case where the resist film is exposed by utilizing an electronbeam, the formation procedure differs between cases, wherein anacceleration voltage is 10 keV or is 20 keV or more.

(i) The case of 10 keV

As shown in FIG. 17A, the phase shift film 4 is formed on thetransparent substrate 1, the resist film 5 is formed on this phase shiftfilm 4 and the static charge prevention film 6 made of conductivepolymer is formed on this resist film 5.

Next, the resist film 5 is exposed by an electron beam. After that,through cleaning with water the static charge prevention film 6 isremoved.

Next, the resist film 5 is developed. After that, etching of the phaseshifter film is carried out. After that, the resist film is removed.

Or, as shown in FIG. 17B, the phase shift film 4 is formed on thetransparent substrate 1, a metal film 6 b is formed on this phase shiftfilm 4, the resist film 5 is formed on this metal film 6 b and a staticcharge prevention film 6 a made of conductive polymer is formed on thisresist film 5.

Next, the resist film 5 is exposed by an electron beam. After that, thestatic charge prevention film 6 is removed through cleaning with water.

Next, the resist film 5 is developed. After that, etching of the metalfilm 6 b is carried out.

Next, etching of the phase shifter film is carried out. After that, theresist film is removed. After that, the metal film is removed.

Or, in the case as shown in FIG. 17B, the following manufacturingmethod, as a well-developed manufacturing method, can be adopted afterthe resist film is removed.

After the resist film is removed another resist film is formed. Afterthat, a conductive film is formed on this resist film.

Next, the resist film is exposed by an electron beam (the resist is madeto remain on the parts through which no light transmits at the time ofexposure of the substrate).

Next, the static charge prevention film is removed through cleaning withwater. After that, the resist film is developed. After that, etching ofthe metal film is carried out. After that, the resist film is removed.

(ii) The case of 20 keV or more

In the case of the blanks structure for a phase shift mask as shown inFIG. 17A, the phase shift mask is formed during the same procedure as inthe above case of 10 keV.

And, in the case of the blanks structure for a phase shift mask as shownin FIG. 17B, the formation of the static charge prevention film 6 a madeof conductive polymer becomes unnecessary since the metal film 6 bfunctions as a static charge prevention film. Here, in the case of theabove described well-developed manufacturing method, the static chargeprevention film 6 a made of conductive polymer is necessary.

(2) The case where the resist film is exposed by utilizing a laser

In the case of the blanks structure for a phase shift mask as shown inFIG. 17A, the formation of the static charge prevention film 6 made ofconductive polymer is unnecessary.

In the case of the blanks structure for a phase shift mask as shown inFIG. 17B, the formation of the static charge prevention film 6 b made ofconductive polymer is unnecessary. And, here, in this case of the abovedescribed well-developed manufacturing method, the formation of thestatic charge prevention film 6 is unnecessary.

Sixth Embodiment

Next, with respect to phase shift masks in the above described first Tofifth embodiments, a defect inspection method and a defect correctionmethod in the case that a residue defect (black defect) 50 or a pinholedefect (white defect) 51 occur as shown in FIG. 18 are described.

First, with respect to a manufacturing phase shift mask, a defectinspection of chip comparison type is carried out by using a lighttransmission type defect inspection device.

This defect inspection device carries out an inspection by using lightfrom the light source of a mercury lamp.

As a result of the inspection, residue defects, where residues of thephase shifter film remain in the place that the pattern should beetched, and pinhole defects, wherein the positions where the phaseshifter film should remain have been missed so that pinholes or missingparts occur, are detected.

Next, these defects are corrected. As for the residue defects, a laserblow correction device by means of a YAG laser which is used for aconventional photo mask is utilized.

In addition, as another method removal can be carried out through assistetching by means of the gas introduction of spatter etching by an FIB.

In addition, though in the above described defect inspection device, theinspection is carried out with light from the light source of a mercurylamp, the residue defects can be corrected by the same method even inthe case where the inspection is carried out with light from the lightsource of a laser.

Next, as for the pinhole defects, the correction is carried out byfilling in the pinhole defect parts through the deposition of carbonbased film 52 by an FIB assist deposition method which is used for aconventional photo mask.

In this manner, an excellent phase shift mask can be gained of which thecarbon based film 52 will not peel off even in the case that thecorrected phase shift mask is cleaned.

Next, an exposure method using the above described phase shift mask isdescribed.

In the case that this phase shift mask is used, the phase shift mask isformed with the film thickness of approximately 680 Å to 2600 Å as shownin the film thickness dimension (ds) of Tables 6 to 8. Therefore, itbecomes possible to give the phase difference of 180° with respect tothe exposure light, which is the diagonal component included in theexposure light as shown in FIG. 19, since the phase shifter film isformed with approximately half the film thickness of a conventionalphase shifter film.

As a result, as shown in FIG. 20, in the case that contact holes of, forexample, 0.25 μm are attempted to be opened it becomes possible totolerate a focus shift of 1.2 μm. In addition, in the case of aconventionally used photo mask, a focus shift of only 0.6 μm can betolerated when contact holes of the same 0.25 μm are opened as shown inFIG. 21.

In addition, in an exposure device of which the coherency is 0.3 to 0.7,preferably 0.6 to 0.7, it becomes possible to significantly increase thefocal depth in comparison with a conventional photo mask as shown inFIG. 22.

Here, though FIGS. 20 to 22 show results in the case that a scalingprojection exposure device, of 5:1, is used, scaling projection exposuredevices of which the scaling ratios are 4:1 and 2.5:1 or a projectionexposure device of 1:1 may be used so that the same working effects canbe gained. Furthermore, a close contact exposure or a proximityexposure, in addition to the projection exposure device, can be used togain the same effects. Moreover, the above described exposure method cangain the same working effects by using any of a g-line, an i-line, a KrFlaser, or the like.

As described above, according to the exposure method using a phase shiftmask in this embodiment, it becomes possible to prevent exposure defectsfrom occurring and, therefore, it becomes possible to increase the yieldin the manufacturing steps of a semiconductor device. This exposuremethod can be effectively used in the manufacturing steps ofsemiconductor devices such as 64M, 128M, 256M or 1G DRAM, SRAM, flashmemory, ASIC, micro computer, GaAs, or the like, and, furthermore, itbecomes possible to satisfactorily use this in the manufacturing stepsof single semiconductor device or a liquid crystal display.

Here, the embodiments disclosed herein are illustrative from all pointsof view and should not be considered as limitative. The technical scopeof the present invention is defined not by the above description but,rather, by the scope of the claims and is intended to include equivalentmeanings of the scope of the claims and all of the modifications withinthe scope.

As described above, according to a phase shift mask and a processthereof, or the like, based on this invention, high transmittance can begained in the ArF laser exposure light wavelength (193 nm) or in the KrFlaser exposure light wavelength (248 nm). In addition, a low defecthalftone phase shift mask can be gained. Since this is a film, formed bylow pressure sputtering, adopting the LTS system, the density of activegases or inert gases becomes low so that grains of molybdenum silicidespattered from the sputtering target reach the substrate with a highaccuracy of directness and a film with a high density, that is to say, afilm of high refraction can be gained.

In addition, since the T/S distance is sufficiently large, the effectsgained from reactive gases reaching the sputtering target become smallerso as to reduce oxidation and nitriding of the target and, thereby,factors of defect occurrence, such as particles of the mask or pinholes,can be avoided.

In addition, reactive gases do not reach the sputtering target to agreat degree, even when the gases are supplied in a large volume and,therefore, oxidation and nitriding occur sufficiently on the substrateso that it becomes possible to gain a film of high transmittance.

This invention relates to a phase shift mask and, in particular, relatesto a structure of an attenuation type phase shift mask which attenuateslight of exposure wavelength, and a process thereof, as well as providesa halftone type phase shift mask which is applicable to an ArF laser ora KrF laser by using molybdenum silicide based materials. In addition,in connection with this phase shift mask, a process for gaining thatphase shift mask as well as a phase shifter film and a process thereof,blanks for a phase shift mask and a process thereof, an exposure methodby using that phase shift mask, a semiconductor device manufactured byusing that phase shift mask, a defect inspection method of that phaseshift mask and a defect correction method of that phase shift mask areprovided.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

1. A process for making a phase shifter film used for a phase shiftmask, characterized in that said phase shifter film is formed by using areactive long throw sputtering method; wherein said reactive long throwsputtering method separately introduces a reactive gas into a substrateside and an inert gas into a target side, respectively; wherein thepressure is 7.5×10⁻⁴ Torr or less; wherein the distance between saidtarget and said substrate is 100 mm or more; and wherein the flow amountratio of said reactive gas to said inert gas is 50%≦reactive gas/inertgas≦80%.
 2. The process for a phase shifter film according to claim 1,wherein said step of forming a phase shifter film further includes thestep of carrying out a heat process of 200 degrees (° C.) or more afterforming said phase shifter film.
 3. The process for a phase shifter filmaccording to claim 1, wherein said phase shifter film is made of amolybdenum silicide oxide nitride.